Volt/Ohm/Amp Meters

SKU: RVI-11485Duration: 20 Minutes

Volts, ohms and amps are important characteristics of all electrical circuits. There are dedicated instruments for measuring each of these quantities, but it is more common to use a single meter that is capable of measuring all three. This interactive online course covers how to take voltage, amperage, and resistance measurements, as well as the precautions to take when making such electrical measurements.

Course Details

Specs

Training Time: 20 minutes

Compatibility: Desktop, Tablet, Phone

Based on: Industry Standards and Best Practices

Languages: English

Learning Objectives

  • Describe a digital multimeter
  • Describe how to make a voltage measurement
  • Describe how to make an amperage measurement
  • Describe how make a resistance measurement
  • List precautions to be taken when making electrical measurements

Key Questions

The following key questions are answered in this module:

What is a multimeter?
A digital multimeter is a single instrument that is capable of measuring voltage, current, and resistance. It is very useful for troubleshooting electrical circuits and equipment.

Define voltage measurement.
Voltage is a measure of the charge potential between any two points in an electrical circuit. The measurement can be made by simply contacting the probes of the meter to the appropriate points in the circuit. Voltage readings can be relative or absolute. Absolute readings are those which are measured against a reference, or ground point. Relative measurements, or voltage drops, are those which are made between any two arbitrary points in a circuit.

Define amperage measurement.
The flow of electrical current can be measured by a digital multimeter. The unit of measurement is amperes, often shortened to "amps." In order to use a digital multimeter as an ammeter, the main selection dial needs to be set to the correct current measurement range, and one of the leads needs to be placed in a current measuring port. To measure current, electricity must flow through the meter. This requires disconnecting the power source, connecting the meter into the circuit, and then reconnecting the power.

Define resistance measurement.
The third type of measurement that can be made with a multimeter is resistance. The resistance of a component is a measure of its ability to allow a flow of electrical current. Electrical resistance is measured in ohms. The lower the ohm value, the less the resistance and the greater the electrical flow.

What does continuity mean in terms of electricity?
Continuity refers to the existence or lack of existence of a conductive path for electrical current through a component or circuit. For example, a fuse may visually appear to be ok, but has in fact been overloaded, or "blown" by excessive current. Testing for continuity will quickly show an infinite resistance, indicating that the fuse is bad.

Sample Video Transcript

Below is a transcript of the video sample provided for this module:

Resistance measurements can be very helpful in troubleshooting. The resistance of components can be compared to their design specifications, or components can be checked for continuity. Continuity refers to the existence or lack of existence of a conductive path for electrical current through a component or circuit. For example, a fuse may visually appear to be ok, but has in fact been overloaded, or “blown” by excessive current. Testing for continuity will quickly show an infinite resistance, indicating that the fuse is bad. Many meters add the convenience of an audio indication when continuity testing. If a component or circuit is good, or has continuity, it will beep when the probes are applied to the circuit. This feature can speed up a search for a broken wire or bad component.
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